SDS-loading dye recipe - pH-sensitive loading dye recipe (Oct/12/2010 )

Hi, I'm looking for the recipe of a pH-sensitive loading dye for SDS-PAGE. We have it in the lab (self-made), but nobody has the recipe. It is colored orange, but the moment you add the protein sample to it, it turns blue. Can anybody help me with this?
Thanks a lot!

Your Google-Fu is weak, young one!

Sample loading buffer (Laemmli loading dye) 3X stock:
1M Tris-Cl pH 6.8 2.4 ml
20% SDS 3 ml
Glycerol (100%) 3 ml
B-mercaptoethanol 1.6 ml
Bromophenol blue 0.006g
10 ml (store 4°C)

From: here

K.B. on Tue Oct 12 22:08:08 2010 said:

Your Google-Fu is weak, young one!

Sample loading buffer (Laemmli loading dye) 3X stock:
1M Tris-Cl pH 6.8 2.4 ml
20% SDS 3 ml
Glycerol (100%) 3 ml
B-mercaptoethanol 1.6 ml
Bromophenol blue 0.006g
10 ml (store 4°C)

From: here

Yes, it is - as it should be. Bromophenol blue is pH-sensitive dye, it's starts to change colour below pH ~5 and is yellow at pH ~3. Usually those non-blue buffers that turn blue after adding a protein are incorrectly made "standard" sample buffers. If you really want colour-changing buffers, just skip Tris and/or add some more acidic buffer.

K.B. on Fri Oct 15 18:59:16 2010 said:

Yes, it is - as it should be. Bromophenol blue is pH-sensitive dye, it's starts to change colour below pH ~5 and is yellow at pH ~3. Usually those non-blue buffers that turn blue after adding a protein are incorrectly made "standard" sample buffers. If you really want colour-changing buffers, just skip Tris and/or add some more acidic buffer.